Beating heart controller and simulator

ABSTRACT

Systems, devices and methods for a surgical training tool that drives movement of an organ in order to reproduce a movement of that organ to mimic the conditions of a live surgical procedure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/167,845 filed May 27, 2016, which is a non-provisional of U.S.Provisional Patent Application No. 62/166,951 filed May 27, 2015, thecontents of which are incorporated herein by reference in theirentireties.

FIELD OF THE INVENTION

The present invention relates to a surgical training tool that drivesmovement of an organ in order to reproduce a movement of that organ tomimic the conditions of a live surgical procedure. For example, actualsurgical procedures on cardiac tissue can take place while the cardiactissue cycles through contraction and dilation of the heart muscle. Byproviding a simulated model of a beating heart, a physician can benefitfrom training on a model that mimics the natural movement of hearttissue in a realistic but simulated manner. The purpose of the inventionis to provide portable a means for more realistic training and productdevelopment for procedures on or around the heart. Cadaver hearts aredeflated and lack the realism of a living beating heart so training witha beating heart simulator enhances the effectiveness of the training.

BACKGROUND OF THE INVENTION

As medical technology advances there is a need for physicians topractice new surgical techniques using novel treatments as well aspractice existing surgical skills using novel devices. There is a clearbenefit to patients if a physician can train on an accurate model whenpreparing for an unfamiliar surgical procedure or when using anunfamiliar device. The need for such training is even more critical whenthe operative field includes a target organ that undergoes cyclicmotion.

Cardiac surgery is one specific area that can benefit from an accuratetraining model. Traditionally, physicians would arrest the heart tocease or slow motion of the cardiac tissue. In order to avoid thecomplications that are associated with arresting heart motion, manycardiac procedures involve beating heart surgery where the physicianperforms the procedure while the cardiac tissue moves through a cyclicrhythm indicative of regular cardiac function. In the field of beatingheart surgery, it is known to use a prosthetic model of a beating heartto simulate clinical situations of beating heart surgery. A prostheticheart model attempts to duplicate the exposure and feel of a beatingheart during surgery, and allows both the surgeon-in-training as well asthe veteran surgeon the opportunity to develop skills needed forconsistent results when performing cardiac surgery on the non-arrestedheart.

Existing training models are disclosed in U.S. Pat. No. 6,685,481 toChamberlain; U.S. Pat. No. 7,798,815 to Ramphal et al.; and U.S. Pat.No. 8,834,172 to Rubinstein et al. the entirety of each of which isincorporated by reference. However, these approaches either rely on: anartificial heart model specifically fabricated for the procedure (e.g.,U.S. Pat. No. 6,685,481 to Chamberlain); animal organs to simulate humanorgans and positioned the non-human tissue within a mock chest cavity(e.g., U.S. Pat. No. 7,798,815 to Ramphal et al.); or rely on asimulated model where a tissue equivalent material includes an array ofelectrodes to form an artificial heart on which the simulated procedureis to be performed (e.g., U.S. Pat. No. 8,834,172 to Rubinstein et al.)

A downside of such artificial training models, apart from the costinvolved in creating the artificial models, is that the artificial modelmay not properly represent the variation in anatomy that a physicianwill encounter when performing an actual procedure. For instance, theanatomy of many patients requiring cardiac surgery will be less thanideal due to the patient's age, obesity, scar tissue, as well as avariety of other conditions that affect individuals.

FIG. 1 provides a partial view of a body 2 to illustrate some of theproblems that a physician encounters when performing a surgicalprocedure on organs within the body 2. The present example shows a heart10 within a thoracic cavity that is encased by a ribcage 4 and sternum6. As noted above, existing training models attempt to recreate theorgan and surrounding environment but such models often cannot replicatethe various tissue and anatomical structures that are found in humanpatients. Moreover, a physician can benefit from having to perform theprocedure on the heart 10 while avoiding the various obstacles caused bythe various tissue, anatomic structures, as well as non-target organs.In many cases, the training can involve minimizing damage to suchtissue, anatomic structures, as well as non-target organs.

Virtual reality simulators may be able to provide a realistic patientanatomy, but such systems do not yet provide realistic physician topatient interface and are limited given the costs as well as environmentin which they can be properly deployed.

In view of the above, there remains a need for a cardiac model thatallows for a beating heart model that presents the challenges couldsimulate the range of normal and abnormal heart rhythms that may ariseduring surgery, such as those resulting from intra-operative events suchas admission of drugs or from ventricular fibrillation.

It would be useful to have a beating heart simulator that provides arealistic environment for surgical training, including the simulation ofthe range of cardiac movement typically encountered in heart surgery.

The present invention provides such an apparatus, system, and methodthat is able to animate a cadaver heart. The present invention canprovide a portable apparatus for more realistic training as well asproduct development for procedures on or around cardiac tissue usinghuman cadaver hearts that are either removed from the body of thecadaver, or remain within the cadaver such that the surrounding anatomyprovides a realistic environment for either training or productdevelopment purposes.

SUMMARY OF THE INVENTION

The present disclosure includes methods and devices for preparing atraining model by animating a heart of a cadaver. In one variation amethod for animating a heart includes advancing a first catheter havinga first expandable member into the cadaver; advancing a second catheterhaving a second expandable member into the cadaver; positioning thefirst expandable member into a first ventricle of the cadaver heart;positioning the second expandable member into a second ventricle of thecadaver heart; coupling the first catheter to a first fluid path, thefirst fluid path being in fluid communication with a positive pressuresource; coupling the second catheter to a second fluid path, the secondfluid path being in fluid communication with the positive pressuresource that provides a fluid flow; and monitoring a parameter of thefluid flow in the first catheter and the second catheter to control thefluid flow in the first fluid path and the second fluid path topressurize and depressurize the first expandable member and the secondexpandable member respectively to produce a beating pattern in thecadaver heart.

A variation of the method includes the first fluid path, which comprisesa first valve, and where the second fluid path comprises a second valve.In an additional variation, the method further includes an adjustablevalve, where the first fluid path and second fluid path are fluidlyisolated in the adjustable valve.

The method can monitor a parameter of the fluid flow that comprises aparameter selected from a group consisting of a time of flow, a volumeof flow, a pressure, and a combination thereof.

In an additional variation, the method can also include advancing athird catheter having a third expandable member into the cadaver;positioning the third expandable member into a first atrium of thecadaver heart; coupling the third catheter to a third valve that isfluidly coupled to the positive pressure source; and where monitoringthe parameter of the fluid flow further comprises monitoring theparameter of the fluid flow in the third catheter to control the thirdvalve to pressurize and depressurize the third expandable member.

In a further variation, the method includes advancing a fourth catheterhaving a fourth expandable member into the cadaver; positioning thefourth expandable member into a second atrium of the cadaver heart;coupling the fourth catheter to a fourth valve that is fluidly coupledto the positive pressure source; and where monitoring the parameter ofthe fluid flow further comprises monitoring the parameter of the fluidflow in the fourth catheter to control the fourth valve to pressurizeand depressurize the fourth expandable member.

The method can include a positive pressure source comprising a pluralityof inflation sources where at least a first inflation source is fluidlycoupled to the first valve and where a second inflation source isfluidly coupled to the second valve.

A variation of the method can include advancing the first cathetermember into the cadaver by advancing the first catheter into a vascularbody in the cadaver and fluidly coupled to the heart the cadaver.

The method can optionally include detaching a stiffening member from thefirst catheter prior to coupling the first catheter to the first fluidpath.

The present disclosure also includes a system for displacing a hearttissue within a heart to reproduce a beating pattern. One variation ofthe system includes a plurality of tubes, each of the plurality of tubesbeing flexible to permit navigation through tortuous anatomy and havingan expandable member coupled to a distal portion and a connector at aproximal portion, each of the plurality of tubes optionally includes atleast one reinforcing member detachably coupled thereto, where thereinforcing member permits navigation of the plurality of tubes througha vascular lumen that is fluidly coupled to the heart to permitpositioning of the expandable member in a chamber of the heart; a valveassembly configured to be coupled to a pressure source, the valveassembly having a plurality of ports; a controller coupled to the valveassembly and configured to operate the valve assembly to selectivelycontrol flow from the pressure source to the plurality of ports tocreate a plurality of fluid paths between the pressure source and eachof the plurality of ports, such that the plurality of fluid paths areable to pressurize the expandable members when placed within the heartto reproduce the beating pattern.

A variation of the system includes a valve assembly that comprises atleast two valves, each having at least one port. In another variation,the valve assembly comprises at least four valves, each having at leastone port.

Variations of the device include a first expandable member for at leastone of the plurality of tubes comprises a first color and where a secondexpandable member for at least one of the tubes comprises a secondcolor, where the first color and second color are visuallydistinguishable. Alternatively, or in combination, a first tube of theplurality of tubes comprises a first color and where a second tube ofthe plurality of comprises a second color, where the first color andsecond color are visually distinguishable.

The system of the present disclosure can comprise a controller that isconfigured to selectively control flow from the pressure source to theplurality of ports to simulate a beating heart pattern selected from thegroup consisting of: a normal beating heart rate from 60 to 100 beatsper minute, a tachycardia rate, an atrial fibrillation, and aventricular fibrillation.

Variations of the device can include a configuration where the at leastone tube of the plurality of tubes comprises an expandable member thatis detachable from a body of the tube. Furthermore, at least one tube ofthe plurality of tubes comprises an expandable members having anon-spherical expanded shape to conform to a chamber of the heart.

The expandable members can be non-distensible, distensible, or acombination thereof.

The system can include a controller that monitors a parameter of thefluid flow in at least one of the fluid paths of the plurality of fluidpaths to selectively control flow from the pressure source to theplurality of fluid paths. Such parameters can include any fluidparameters, including but not limited to a time of flow in, a volume offlow, a pressure, a time of flow, and a combination thereof. The systemcan be configured to provide instantly switchable heart rhythms.

In additional variations, the system is lightweight to provide aportable beating heart simulator.

Variations of the access device and procedures described herein includecombinations of features of the various embodiments or combination ofthe embodiments themselves wherever possible.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 provides a partial view of a body to illustrate anatomy of that aphysician encounters when performing a surgical procedure on organs.

FIG. 2 illustrates a partial view of a cadaver showing the heart withinthe cadaver and advancement of devices for animating the heart.

FIG. 3 illustrates a partial cross sectional view of a heart and majorvessels providing an access to the chambers of the heart with thedevices positioned within the chambers of the heart.

FIG. 4 illustrates a condition in the heart where expandable members arepositioned into each respective chamber of the heart.

FIG. 5 illustrates a condition where the tubes are either directlycoupled (via the connectors disclosed above) or indirectly coupled (viaan intermediate extension member) to one or more connectors or fittingson a valve assembly.

FIG. 6 illustrates a schematic of one variation of a system as disclosedherein.

FIGS. 7A and 7B illustrate an example of an expandable device.

FIG. 8A illustrates a schematic of a simple system that is operated by amotor cylinder combination and single valve that establishes flowpathsthe various expandable members.

FIG. 8B shows the fluid path branching into two flowpaths and mayoptionally branch into more paths towards the organ.

FIG. 9 shows an example of an analog system.

FIG. 10 shows an example of a digital system.

FIG. 11 shows an additional example of controlling the heart rhythm ofthe animated heart.

DETAILED DESCRIPTION

Methods and devices described herein provide for preparing a trainingmodel of an animated heart typically in a cadaver. The presentdisclosure also includes a system for displacing a heart tissue within aheart to reproduce a beating pattern.

FIG. 2 illustrates a partial view of a cadaver 2 showing the heart 10within the cadaver 2. In the illustration, the heart is shown as exposedfor purposes of discussing the procedure of animating a heart 10 of acadaver 2. As noted herein, the process of animating a heart in acadaver can be useful to provide a training model that allows aphysician to practice a procedure in a realistic environment.Alternatively, animating the heart 10 can provide a background for thedevelopment of new procedures and/or devices

FIG. 2 illustrates a condition where one or more tubes 102, 104 areadvanced through openings in the body (not shown) for ultimate placementin any one of the chambers of the heart 10. As discussed below,variations of the methods and device can include placement of anexpandable member in either a right ventricle 16 or left ventricle 18 ofthe heart. In additional variations, expandable members can bepositioned in the right and left atriums 12, 14. Variations of themethod can even include positioning of an expandable member into asingle chamber or positioning of an expandable member across both anatrium and ventricle. In some variations, positioning of the tubing 102,104 into the chambers of the heart 10 occurs via navigation of thetubing 102, 104 through one or more major vessels 20 that provide a pathinto the heart 10. Because the method is being performed on a cadaver 2the entry points of the tubing 102, 104 can be made at a convenientlocation within the body that otherwise wouldn't be possible whenperforming a procedure on a live subject. For example, if the openingsdo not impact the intended training procedure, openings can be made ineither (or both) the anterior, posterior and lateral sides of thecadaver 2 in order to successfully navigate the tubing and expandablemembers to the desired location. Again, as noted above, most methodsunder the present disclosure allow for the heart 10 to remain within thecadaver 2 during performance of the training procedure. Alternatively orin combination the insertion points can be conventional access pointsvia the neck, legs, or endoscopic access points to access the vesselsleading to the heart.

FIG. 2 also illustrates the tubing 102 and 104 including connectors 106and 108. As discussed below, the connectors allow for direct or indirectcoupling of the tubing 102 104 to a valve system. However, in order tonavigate the tubing to the intended region of the heart 10, theconnectors can optionally remain unconnected so that a stiffening orsupport member 110 assist in placement of the tubing. The support member110 can be a tube or member that is stiffer than the tubing.Alternatively, or in combination, the support member 110 can be asteerable catheter, scope, and/or device that assists in navigation ofthe tubing to the desired target. Variation of the method and device caninclude the use of a single support member 110 for each tube that isintended to be placed. Alternatively, each tube can include its ownsupport member.

Many alternative access paths exist for installation of the inflationdevices, which are dependent upon the tissue parameters and/or thebiodynamic action desired. These include the sternotomy, thoracotomy,mid-clavicular, subxiphoid, supra-manubrium, trans-diaphragmatic, orposterior approaches. Each offers advantages and may be selected basedon the purpose of the animation. If a naïve chest wall is desired forthe purpose of teaching a minimally invasive procedure, a mid-clavicularor posterior approach may be desired.

In one variation, the inflation devices may be inserted through a smallthoracotomy in the upper right thoracic quadrant. This incision exposesthe superior aspects such as the aorta or right brachiocephalic artery,the superior vena cava or jugular vein, and the main pulmonary arteryand/or the right bifurcated branch.

The inflation devices of adequate size may be placed into the vascularaccesses and into respective regions of the heart: through the superiorvena cava to the right ventricle through the tricuspid valve;alternatively, through the inferior vena cava into the right atrium tothe right ventricle through the tricuspid valve. The inflation devicefor the right atrium would follow and sit above the tricuspid valve,facilitated by a “full right ventricle” and a blocked pulmonic valve bythe aforementioned inflation device.

The left ventricle may be cannulated by an incision in thebrachiocephalic artery or the aortic root, and placed retrograde throughthe aortic valve. The left atrium may be accessed through a trans-septalincision and the right atrium via the superior vena cava or right atrialappendage in which a purse string is placed to secure it. The leftatrium may be accessed by a right thoracotomy or by ports to allowthoracoscopic dissection of the right superior lung, which allows foraccess of the distal branch or the right superior pulmonary vein. Toaccess the left atrium with better success of achieving left atrialappendage filling is via a right thoracotomy, or placement of ports toallow thoracoscopic dissection of the right superior lung, accessing adistal branch or the right superior pulmonary vein. Additionally, a longwire wound or a compliant guide wire may be used to place the inflationdevices. This guide wire may be used internally or externally forplacing the inflation device. The left atrial appendage may also beapproached through the right superior pulmonary vein ostium of the leftatrium and placing the inflation device the left atrial appendage by athoracoscopic instrument through a port placed in the upper left chestwall. Pressure may be applied to the floor of the left atrium to guidethe catheter and balloon to the left atrial appendage. Additionally,other steering devices and methods not described may also be used toplace of the inflation devices.

FIG. 3 illustrates a partial cross sectional view of a heart 10 andmajor vessels 200 providing an access to the chambers of the heart 10.Although the heart is illustrated alone, it is understood that, in mostvariations of the process, the tubing 102 104 are navigated through thebody of the cadaver. FIG. 3 illustrates the tubing 102 and associatedexpandable member 112 advanced into the right ventricle 16 while asecond tubing 104 and associated expandable member 114 is advanced intothe left ventricle 18. The order of advancement of the expandablemembers into the ventricles can be based on convenience. Alternatively,variations of the device and method include a single expandable memberadvanced into a single ventricle to drive the movement of the heart 10.In an additional variation, a single expandable member can be positionedacross adjacent chambers. As discussed below, additional expandablemembers and tubing can be positioned into each of the chambers of theheart (including the atriums 12 14). Furthermore, an expandable membercan be positioned into the atrial appendage (not shown) or even into oneor more of the major arteries 20. In an alternate variation, the tubingcan include smaller expandable sections located proximal to the distalexpandable members such that the smaller proximal expandable membersprovide a degree of movement and animation of the major vessels 20.

FIG. 4 illustrates a condition in the heart 10 where expandable members112, 114, 116, 118 are positioned into each respective chamber 12, 14,16, 18 of the heart. As shown, expandable member can be introduce intoany vessel allowing access to the desired chamber. Moreover, twoexpandable members can be positioned through the same vessel. As shown,one or more of the expandable members can be shaped to match a profileof the heart chamber. Furthermore, the expandable members can benon-distensible or distensible in construction. Moreover, any one of theexpandable members can include a combination of a distensible portionand a non-distensible portion (i.e., by the joining of respectivematerials or by positioning of a non-distensible constraint on adistensible material).

FIG. 5 illustrates a condition where the tubes are either directlycoupled (via the connectors disclosed above) or indirectly coupled (viaan intermediate extension member) to one or more connectors or fittings140 on a valve assembly 130. In the illustrated variation, the valveassembly 130 comprises individual valves 132, 134, 136, 138 that are influid communication with a pressure source 160. The pressure source 160can be a standalone source of fluid (either a liquid and/or a gas) suchas air, carbon dioxide, or nitrous oxide. The pressure source 160 can bean air compressor, hospital air or carbon dioxide or compressed gas in atank. In certain examples, the pressure source was set to between 5 to30 psi in order to inflate the chambers of the heart within an optimaltimeframe. The typical inflation pressure for a heart is only a few psiso in certain variations, the system times the valves to prevent theinflatable devices from fully inflating to a point where the heart canbe damaged. Moreover, the system can include a single valve thatcontrols all of the expandable members or multiple valves per expandablemember.

Typically, the valve assembly 130 is coupled to a controller 152 that isconfigured to operate the valve assembly to selectively control flowfrom the pressure source 160 to the plurality of ports or valves tocreate a plurality of fluid paths 122, 124, 126, 128 between thepressure source and each of the plurality of expandable memberspositioned in the heart 10, such that the plurality of fluid paths 122,124, 126, 128 are able to pressurize the respective expandable membersto reproduce the beating pattern. The system can also include auxiliarycomponents such as a fluid source 162 in the event that the trainingmodel requires a fluid to represent the effects of blood within theoperative space.

FIG. 6 illustrates a schematic of one variation of a system as disclosedherein. In this example the valve assembly 130 comprises individualvalves 132, 134, 136, 138 that are in fluid communication with apressure source 160 as well as the respective expandable members 112,114, 116, 118. In the illustrated example, the pressure source 160pressurizes the valve assembly such that the valves (being controlled asdiscussed herein) establish flow lines to the expandable members 112 114in the ventricles. The same valve assembly 130 can establish alternateflow lines between expandable members 116 118 in the atriums and anexhaust 164 that allows deflation or decompression of the expandablemembers 116 118 in the atriums. The valves can be controlled as notedherein to provide beating heart patterns to simulate a beating heartpattern selected from the group consisting of: a normal beating heartrate from 60 to 100 beats per minute, a tachycardia rate, an atrialfibrillation, and a ventricular fibrillation. Moreover, the system 150shown in FIG. 5 can be configured such that the controller 152 monitorsa parameter of the fluid flow in at least one of the fluid paths of theplurality of fluid paths to selectively control flow from the pressuresource to the plurality of fluid paths. The parameter can be any fluidparameter that allows for obtaining the simulated beating heart pattern.Such parameters include, but are not limited to: a volume of flow, apressure, a time of flow, and a combination thereof.

In one variation, the valve assembly 130 is sequenced with a controller152 that is programmed to simulate various heart rates and rhythmsincluding tachycardia, atrial fibrillation, ventricle fibrillationetcetera. In addition to preprogrammed rhythms each valve could becontrolled by a variable input signal. The controller 152 can comprise aProgrammable Logic Controller (PLC). Alternatively, the valve assemblycan be sequenced using a microcontroller, Personal Computer (PC), orField-Programmable Gate Array (FPGA).

The input to the valves is preferably a readily available gas such asair, carbon dioxide, or nitrous oxide. The source can be an aircompressor, hospital air or carbon dioxide or compressed gas in a tank.Alternatively, the pressure source can supply such as water. The inputpressure to the valves is in the range of 5 to 30 psi in order toinflate the chambers of the heart within the timeframe required.

The unit can be battery powered or can rely upon standard 120v AC power.supplied in order to accommodate various international powerrequirements. The output of the power supply can be classified as LowVoltage, Limited Energy (LVLE) for electrical safety. The vales and thePLC are powered by 24 VDC.

The beating heart simulator can use any number of inflatable device suchas an elastic balloon or non-elastic member like a bag ornon-distensible balloon that is attached to the end of an elastic tube.FIGS. 7A and 7B illustrate one example of such an inflatable device 100.As shown, the inflatable device 100 can include an elongate tube 102coupled to an expandable member 112. The configuration can comprise aballoon-catheter configuration. Alternatively, the expandable member 112can be detachable from the tube 102 to allow the user to couple anexpandable member having desired properties such as elasticity,non-distensible, shape, etc. As shown, the device 100 can optionallyinclude a support member 110 removably coupled to the tube 102 and/orexpandable member 112. The support member 110 can comprise a stiffeningtube, scope, and/or a steerable device that assists the user inpositioning the device 100 through the anatomy of the cadaver and intothe heart. In order to achieve realistic simulation, a tube andexpandable member are positioned in each of the four chambers the heart.In an alternate variation, the simulator can be simplified by connectingthe ventricle and the atrium together with a wye connector andcontrolled with a single valve. In addition, as described above, an evensimpler method is to only inflate the ventricles of the heart since theyare the largest chambers. The tubing and/or expandable member in systemsthat include a plurality of tubings/expandable member can be visuallydistinguishable via color, shading, printing, etc. to reduce confusionwhen placing the inflatable devices or to direct the user regarding theappropriate chamber for the respective expandable member. FIG. 7Aillustrates the tubing as including an optional connector 106. Once thedevice is positioned and the support member 110 is removed, theconnector 106 can be coupled to a port on the valve (not shown) or to anintermediate connector 120 that ultimately is fluidly coupled to thevalve/pressure source to allow for expansion of the expandable member112 as shown in FIG. 7B.

In an additional variation of the system, the tubing for each inflatabledevice can be connected to a solenoid controllable directional valve. Aquick connect method to attached the tubing is preferred since thetubing and inflatable device will be single use in a cadaverapplication. The exhaust from the directional valve can go toatmosphere, vacuum, or preferably to a pressure relief mechanism tosimulate diastolic pressure.

The system 150 can comprise a digitally-controlled volume and pressureassist device system is described above By using the system, the heartin a cadaver can be reanimated to mimic how a heart beats in a surgicalprocedure. Additionally, while the systems and method disclosed hereinare intended for use in a cadaver, the system may be used to animate asynthetic heart as well

FIG. 8A illustrates a schematic of a simple system that is operated by amotor cylinder combination 150 and single valve 152 that establishesflowpaths the various expandable members 112, 114, 116, 118. As shownthe fluid may be directed into four separate paths. Alternatively, thefluid may branch into two flowpaths 154 and may optionally branch intomore paths towards the organ as shown in FIG. 8B. Once the organ isfilled, it may be emptied and the fluid may passively flow back towardsthe valve due to the pressure gradient imparted by the inflation device.Additionally, the controller may actively impart the fluid flow withnegative pressure to evacuate the inflation device. Depending upon thesetup of the system, the fluid may flow out of the system or berecirculated. For instance, in a closed-loop system, the fluid wouldflow back towards the pump as shown in FIG. 8A. In an open-loop system,the fluid would exit the system from the valve as shown in FIG. 8B.

The system may be orientated in several different configurations. Forinstance, one motor can power the entire system. If one motor powers thesystem, it may optionally be connected to multiple pumps via multiplegears or pulleys to allow pump flow differentiation. Optionally, severalmotors may be used to power the system. When more than one motor isutilized, the motors may be set up in a parallel configuration meaningthat each motor operates a pump independently from one another. In thisconfiguration, the motor(s) may be controlled by a master controller.The motor(s) in the system may be a DC motor, a stepper motor, or anyother motor known in the art. The system may optionally include one ormore pistons and cylinders that may include an input and output for afluid, which may include gas or a liquid.

The motors may be configured manually or electronically to selectivelypump a fluid volume to either fully or partially inflate an inflationdevice. For example, a rotary DC motor may be connected to a piston in acylinder via a variable length connecting rod, which may be configuredto pump the desired fluid volume. Alternatively, a stepper motor can beprogrammed to drive a piston directly to generate the desired fluidvolume. Additionally, a single motor can be connected to multiple pumpsvia gears or pulleys to selectively fill multiple inflation devices withdifferent volumes.

As shown in FIG. 9, an example of the analog system may be used. Thecontrol of the analog system may include the use of pressure gauges anda manually set volume and rate (frequency of beats) by the operator tocontrol the system. The volume is set by a manually adjusted sliding arm149 component attached to the motor 148 on one side and the piston 158or fluid driver on the other. Pressure is monitored at the outflow ofthe fluid to the manifold 130 that distributes the fluid to therespective chambers and inflation devices 112 114. Volumes are adjustedto regulate pressure to a desired set-point—this would be an averagepressure for one chamber and/or for each chamber individually. Also, anexample of the digital system may be used as shown in FIG. 10. Thecontrol of the digital system includes the use of a software managedmicroprocessor system 152 with several inputs and outputs 154 toregulate fluid volume, pressure and frequency/rate of inflation anddeflation. The system can include stepper motors 156 that drive pistons158 which serve as the pressure source.

The system may be controlled by feedback. For instance, pressure andvolume sensors may be used. The speed and/or travel of the motors may bemonitored and may be modified in an open or closed loop manner to obtainthe desired pressure and flow of the system. Pressure may change basedupon the compressibility of the fluid, volume, or rate of flow. Thesystem can be individually regulated by volume or pressure or may beregulated by both volume and pressure. Additionally, other controlmechanisms such as adaptive control and fuzzy control may be utilized.If other control systems are not available, a manual control system mayoptionally work. For instance, a hand pump may be used to operate thesystem.

Safety features may additionally be included that limit pressure offluid flow to avoid rupture of the inflation device or surroundingtissue. For example, a pop-off valve or regulator may be included. Thepop-off valve may be a component of the analog system. A digitalpressure transducer interfaced with the controller may optionally beadded. The pressure transducer may be placed at the exit of the driver,or piston, in the outlet line to the inflation device, or in theinflation device. The pressure transducer prevents the inflation devicefrom damaging the tissue of a subject. The pressure transducers reducethe need to manually interface the system because a pressure set pointmay allow the programmable feature to slow the system to achieve the setpressure and volume without exceeding either. For example, a line maykink, which may result in a failure in that respective chamber, and thepressure transducer will be affected. In another example, pressurelimits set by a microprocessor based controller will have variably setlimits which will automatically limit pressure and/or volume in eachchamber. Additionally, pressure limits set by a microprocessor basedcontroller will have variably set limits which will automatically limitpressure and/or volume in each chamber. The pressure and/or volume setpoint may optionally feature a digital controller.

FIG. 11 shows an additional example of controlling the heart rhythm ofthe animated heart. As shown, a controller mechanism 146 may be added asa monitoring function to the feedback loop that may regulate theinflation response to match the desired rate and heart rhythm. Forinstance, a preset parameter may be chosen to operate to the controllerinterface. As an example, to create an appearance of the left atriumwith atrial fibrillation, the controller interface may be set to aparticular drive rate and inflation volume. The motor 148 would drivethe pump 158 to that volume and flow rate. The monitoring feedback loopwould provide feedback to the controller that the response was withinspecification. If it was not, then the controller would be signaled tochange rate and/or volume, which would alter the stroke length byincreasing or decreasing the volume. The flow rate would be change byincreasing or decreasing the frequency of the stroke.

Additionally, other controller positioning options are available. Withone motor and one pump assembly, a manual controller may be used tocontrol the fluid flow by regulating the motor. The manual controllermay be placed between the motor and pump assembly. In this assembly, apressure transducer may be used to monitor and regulate pressuredelivered with each stroke that feeds a signal that triggers anindication to adjust flow and pressure to nominal levels. With a digitalmicroprocessor controlled system, a plurality of transducers may providefeedback to the microprocessor and may automatically adjust and maintainthe individual drivers to preset or manually inputted parameters intothe digital control system. A touch screen, which also serves to give avisual display of monitored parameters, may be used in this setup.

In addition to atrial fibrillation, other heart rhythms may be mimickedby using similar methods. Please note that other setups utilizing acontroller mechanism and feedback response may be utilized in additionto the method described above.

Additionally, other inflation devices may be utilized in the heart. Forinstance, an inflation device may be optionally be added to the rightatrial appendage. Additionally, the system may work with only oneinflation device. In addition to the heart, inflation devices may beinserted into other organs, such as the lungs. Alternatively, inflationdevices may be placed into the space between the organs. For example, inthe pleural space below the lung and pleural of the lung and thepericardial sac.

Although the present methods and devices have been described in terms ofthe embodiments above, numerous modifications and/or additions to theabove-described preferred embodiments would be readily apparent to oneskilled in the art. It is intended that the scope of the presentinventions extend to all such modifications and/or additions and thatthe scope of the present inventions is limited solely by the claims ofthe invention.

What is claimed is:
 1. A method of operating a training model byanimating a heart within a synthetic chest cavity, the methodcomprising: advancing a first catheter having a first expandable memberinto a vascular body in the synthetic chest cavity, where the vascularbody is fluidly coupled to the heart; advancing a second catheter havinga second expandable member into the synthetic chest cavity; positioningthe first expandable member into a first ventricle of the heart;positioning the second expandable member into a second ventricle of theheart; coupling the first catheter to a first fluid path, the firstfluid path being in fluid communication with a positive pressure source;coupling the second catheter to a second fluid path, the second fluidpath being in fluid communication with the positive pressure source thatprovides a fluid flow; and providing pressure to the first catheter andthe second catheter; and monitoring a parameter of the fluid flow in thefirst catheter and the second catheter to control the fluid flow in thefirst fluid path and the second fluid path to pressurize anddepressurize the first expandable member and the second expandablemember respectively to produce a beating pattern in the heart.
 2. Themethod of claim 1, wherein the first fluid path comprises a first valve,and where the second fluid path comprises a second valve.
 3. The methodof claim 1, further comprising an adjustable valve, where the firstfluid path and second fluid path are fluidly isolated in the adjustablevalve.
 4. The method of claim 1, where the parameter of the fluid flowcomprises a parameter selected from a group consisting of a time offlow, a volume of flow, a pressure, and a combination thereof.
 5. Themethod of claim 1, further comprising: advancing a third catheter havinga third expandable member into the synthetic chest cavity; positioningthe third expandable member into a first atrium of the heart; couplingthe third catheter to a third valve that is fluidly coupled to thepositive pressure source; and where monitoring the parameter of thefluid flow further comprises monitoring the parameter of the fluid flowin the third catheter to control the third valve to pressurize anddepressurize the third expandable member.
 6. The method of claim 5,further comprising: advancing a fourth catheter having a fourthexpandable member into the synthetic chest cavity; positioning thefourth expandable member into a second atrium of the heart; coupling thefourth catheter to a fourth valve that is fluidly coupled to thepositive pressure source; and where monitoring the parameter of thefluid flow further comprises monitoring the parameter of the fluid flowin the fourth catheter to control the fourth valve to pressurize anddepressurize the fourth expandable member.
 7. The method of claim 2,where the positive pressure source comprises a plurality of inflationsources where at least a first inflation source is fluidly coupled tothe first valve and where a second inflation source is fluidly coupledto the second valve.
 8. The method of claim 1, where advancing thesecond catheter into the synthetic chest cavity comprises advancing thesecond catheter into a second vascular body in the synthetic chestcavity, where the second vascular body is fluidly coupled to the heart.9. The method of claim 8, further comprising detaching a stiffeningmember from the first catheter prior to coupling the first catheter tothe first fluid path.
 10. A method of preparing a training model byanimating a heart located in a synthetic chest cavity, the methodcomprising: advancing a first catheter having a first expandable memberinto a vascular body in the synthetic chest cavity that is fluidlycoupled to the heart; advancing a second catheter having a secondexpandable member into the synthetic chest cavity; positioning the firstexpandable member through the synthetic chest cavity and into a firstventricle of the heart; positioning the second expandable member into asecond ventricle of the heart; coupling the first catheter to a firstfluid path, the first fluid path being in fluid communication with apositive pressure source; coupling the second catheter to a second fluidpath, the second fluid path being in fluid communication with thepositive pressure source that provides a fluid flow; and providingpressure to the first catheter and the second catheter; and monitoring aparameter of the fluid flow in the first catheter and the secondcatheter to control the fluid flow in the first fluid path and thesecond fluid path to pressurize and depressurize the first expandablemember and the second expandable member respectively to produce abeating pattern in the heart.
 11. The method of claim 10, wherein thefirst fluid path comprises a first valve, and where the second fluidpath comprises a second valve.
 12. The method of claim 10, furthercomprising an adjustable valve, where the first fluid path and secondfluid path are fluidly isolated in the adjustable valve.
 13. The methodof claim 10, where the parameter of the fluid flow comprises a parameterselected from a group consisting of a time of flow, a volume of flow, apressure, and a combination thereof.
 14. The method of claim 10, furthercomprising: advancing a third catheter having a third expandable memberinto the synthetic chest cavity; positioning the third expandable memberinto a first atrium of the heart; coupling the third catheter to a thirdvalve that is fluidly coupled to the positive pressure source; and wheremonitoring the parameter of the fluid flow further comprises monitoringthe parameter of the fluid flow in the third catheter to control thethird valve to pressurize and depressurize the third expandable member.15. The method of claim 14, further comprising: advancing a fourthcatheter having a fourth expandable member into the synthetic chestcavity; positioning the fourth expandable member into a second atrium ofthe heart; coupling the fourth catheter to a fourth valve that isfluidly coupled to the positive pressure source; and where monitoringthe parameter of the fluid flow further comprises monitoring theparameter of the fluid flow in the fourth catheter to control the fourthvalve to pressurize and depressurize the fourth expandable member. 16.The method of claim 11, where the positive pressure source comprises aplurality of inflation sources where at least a first inflation sourceis fluidly coupled to the first valve and where a second inflationsource is fluidly coupled to the second valve.
 17. The method of claim10, further comprising detaching a stiffening member from the firstcatheter prior to coupling the first catheter to the first fluid path.